<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=
    , initial-scale=1.0">
    <title>Vue-if</title>
    <script src='vue.js'></script>
</head>
<body>
    <div id='app'>
        <p v-if="seen">
            现在看到我了吗
        </p>
    </div>
    <script>
        const app =  new Vue({
            el:'#app',
            data:{
                seen: false
            }
        })
    </script>
</body>
</html>